Preheat the oven to 400°F and lightly grease a small baking sheet with vegetable oil. Set aside.
Remove any green leaves from the cauliflower and trim off the hard part of the base.
In a medium bowl, whisk together the olive oil with the lemon zest and juice, cumin, garlic powder, coriander, salt and pepper.
Use a brush or your hands to spread the marinade evenly over the head of cauliflower. (Any leftovermarinade can be stored in the refrigerator in an airtight container for up to three days and used with meat, fish or other veggies.)
Place the cauliflower on the prepared baking sheet and roast until the surface is dry and lightly browned, 30 to 40 minutes.
Let the cauliflower cool for 10 minutes before cutting it into wedges. Serve warm with fresh grated Parmesan sprinkled over the top. Works great as an appetizer or pair with a green salad.